Determination method, measurement device, and measurement system

The present invention relates to a determination method, a measurement device, and a measurement system.

In recent years, studies on cancer inspection methods using elongated filamentous organisms called nematodes have been actively conducted, and have attracted attention.

This inspection method utilizes chemotaxis or olfactory nerve response based on the olfactory sense of the nematodes. Since the nematodes have a property of liking an odor of urine of a cancer patient and disliking an odor of urine of a healthy person, it is possible to use the nematodes for identification of the presence or absence of cancer and the like by dropping urine of a subject in the vicinity of the nematodes and observing whether the nematodes exhibit the attracting behavior or the repelling behavior for urine.

In using the above method, a method for evaluating the behavior of the nematodes is important, but a method for accurately and inexpensively evaluating the behavior of the nematodes has not been established yet. As technology related to the evaluation of the behavior of the nematodes, for example, Patent Literature 1 is known.

Patent Literature 1 describes technology in which a plate on which nematodes and urine specimens are plotted is irradiated with light from below to capture an image, and quality control of the nematodes is performed on the basis of a temporal change in brightness in a predetermined range in the captured image. This is to evaluate the movement of the nematodes by evaluating the movement of a portion with a high brightness by utilizing the fact that the nematodes appear white and a medium appears black when the plate on which the nematodes are disposed on the medium is irradiated with light and photographed.

However, in the method described in Patent Literature 1, complicated calculation including image processing and the like is required in the calculation of the brightness center of gravity, and there is a problem that the behavior of the nematodes cannot be evaluated unless a computer capable of such processing is used.

In view of the above situation, it is an object of the present invention to provide a novel method for easily determining the behavior of a nematode.

In order to solve the above problem, the present invention provides a determination method including: dropping a liquid containing a biological substance of a subject into a container in which a nematode is movably stored; measuring, as reference amount, an amount related to light in a measurement range in the container irradiated with light before or immediately after the dropping of the liquid; measuring, as a determination amount, an amount related to light in the measurement range in the container irradiated with the light after an observation time provided for movement of the nematode elapses from the dropping of the liquid; and determining whether or not it is considered that the determination amount has decreased by comparison with the reference amount.

According to the present invention, it is possible to determine the change in the amount related to the light in the measurement range before and after the movement of the nematode by the dropping of the liquid. Further, by comparing the reference amount and the determination amount in the same measurement range, even if there is a variation in the illumination condition for each container, the measurement conditions of the reference amount and the determination amount are matched, so that it is possible to accurately determine the change in the amount related to the light. Since the place where the nematode is present in the irradiated container becomes bright, it is possible to determine whether the nematode has exhibited the attracting behavior or the repelling behavior in response to the dropping of the liquid by determining whether or not it is considered that the determination amount has decreased with the above configuration.

In a preferred mode of the present invention, when it is considered that the determination amount has decreased, eligibility for insurance as a healthy person is given to the subject, and when it is considered that the determination amount has increased or when it is considered that there is no change in the determination amount, a notification for prompting an inspection is given.

With such a configuration, it is possible to give eligibility for insurance to the subject for which it is considered that the determination amount has decreased (the nematode has exhibited the repelling behavior), that is, it is considered that a possibility of cancer is low, and for example, it is possible to easily examine eligibility for insurance. Further, when it is considered that the determination amount has increased or when it is considered that there is no change in the determination amount, by giving a notification for prompting an inspection to the subject, an effect of contributing to early detection of cancer is expected.

In a preferred mode of the present invention, when a difference obtained by subtracting the reference amount from the determination amount or a ratio obtained by dividing the determination amount by the reference amount is less than a lower limit value, it is considered that the determination amount has increased. When the difference obtained by subtracting the reference amount from the determination amount or the ratio obtained by dividing the determination amount by the reference amount exceeds an upper limit value, it is considered that the determination amount has increased. When the difference obtained by subtracting the reference amount from the determination amount or the ratio obtained by dividing the determination amount by the reference amount is between the upper limit value and the lower limit value, it is considered that there is no change in the determination amount.

With such a configuration, it is possible to evaluate the change in the determination amount using a quantitative value on the basis of the upper limit value and the lower limit value set in advance.

In a preferred mode of the present invention, light of a specific wavelength is emitted at the time of measuring the reference amount and the determination amount, and amounts related to the light of the specific wavelength are measured as the reference amount and the determination amount, respectively.

With such a configuration, an influence of light other than the irradiation light can be reduced, and an effect of improving accuracy can be expected.

In a preferred mode of the present invention, the container includes a transmissive portion that transmits light on a side surface, and the transmissive portion is irradiated with light from the side surface of the container at the time of measuring the reference amount and the determination amount.

With such a configuration, the determination method according to the present invention can be used under various environments.

In order to solve the above problem, the present invention provides a measurement device for executing the determination method of aspects 1 to 5. The measurement device includes: a main body portion that covers the container; the illuminator that is provided inside a side surface of the main body portion and emits light from a side surface of the container; an input port that is provided in the main body portion to drop the liquid into the container; and a measurement unit that is provided on the main body portion and measures the amount related to the light from above the container.

According to the present invention, the illumination condition or the like can be brought close to a certain level by emitting light by the illuminator included in the main body portion covering the container, so that the effect of further improving the accuracy can be expected. Further, by providing the input port, since the liquid can be dropped in a state where the main body portion covers the container, it is not necessary to move the container or the measurement device when the liquid is dropped, the reference amount and the determination amount can be measured under a certain condition before and after the dropping, and the accuracy is improved.

In a preferred mode of the present invention, the main body portion includes the input port at a position higher than a height of the container.

With such a configuration, since the liquid can be dropped from above, the liquid can be easily dropped into an accurate position even in a state where the main body portion covers the container.

In a preferred mode of the present invention, the measurement device further includes a wheel, and the measurement unit continuously measures the reference amount and the determination amount for a plurality of containers by the measurement device being moved by the wheel.

With such a configuration, it is possible to perform the determination more efficiently.

In a preferred mode of the present invention, the main body portion includes a container introduction port for taking in and out the container on a side surface in a direction substantially perpendicular to a traveling direction of the wheel.

With such a configuration, it is possible to continuously perform the determination for the plurality of containers while moving the measurement device in a certain direction by the wheel, and the determination efficiency is improved.

In order to solve the above problem, the present invention provides a measurement system including the measurement device of aspects 8 or 9 and a floor plate. The floor plate includes a container placement portion on which the container is placed, and a boundary portion that defines a boundary between an inner side and an outer side of the container placement portion, and the wheel travels outside the container placement portion.

According to the present invention, the wheel of the measurement device can move without contacting the container, and the determination can be performed efficiently and accurately. Further, for example, when the boundary portion is expressed by unevenness, it is difficult for the wheel to enter the container placement portion, and efficiency and accuracy can be further improved.

According to the present invention, a novel method for easily determining the behavior of a nematode can be provided.

Hereinafter, a determination method according to an embodiment of the present invention will be described with reference to the drawings. Note that the following embodiments are examples of the present invention, the present invention is not limited to the following embodiments, and various configurations can be adopted.

is a flowchart illustrating a procedure of a determination method in the present embodiment. First, in step S, a reference amount is measured. Here, the reference amount is an amount related to light in a measurement range in a container irradiated with light, and in the present embodiment, an illuminance with the periphery of a dropping position of a liquid containing a biological substance of a subject as a measurement range is measured as the reference amount. In addition, as the amount related to the light, it is possible to use an arbitrary index representing the intensity of light that changes due to the presence of nematodes, including a photometric quantity including a brightness or the like in a captured image of the container. The photometric quantity is a psychophysical quantity obtained by quantifying a radiation amount with the sensitivity of a human eye.

Next, in step S, the liquid containing the biological substance of the subject is dropped into the container as a specimen. It is preferable to drop the liquid to a predetermined dropping position. In the present embodiment, a petri dish with a lid to be described later is used as the container, and the specimen is dropped near the center. Further, in the present embodiment, a liquid obtained by diluting the urine of the subject about 100 to 150 times is used as the liquid containing the biological substance of the subject.

Here, an agar medium or the like is provided on a bottom surface of the container, and the nematodes can freely move. An environment in which the nematodes can move may be provided by any other means. A sufficient number of, for example, about 100 nematodes are added to such a bottom surface in advance, and the behavior of the nematodes can be determined. As the nematode,is suitably used, which has the advantage of having a body length of about 1 mm, having all minimum systems necessary for animals, capable of being bred at room temperature, and being relatively easy to maintain the system.

Next, in step S, the process waits until an observation time provided for the movement of the nematode elapses. The observation time may be arbitrarily determined within a range in which the movement of the nematode can be sufficiently confirmed. For example, various conditions such as 10 seconds, 30 seconds, 60 seconds, 100 seconds, 150 seconds, 210 seconds, 280 seconds, and 360 seconds can be considered. It is preferable to specify and use the observation time at which the attracting behavior or the repelling behavior of the nematodes appears most remarkably by experiments.

When the observation time elapses after the specimen is dropped, the process proceeds to step S, and the determination amount is measured. The determination amount is an amount related to light in the same measurement range as the reference amount, and the same index as the reference amount is used. Here, the measurement range is a range narrower than the entire container in which the nematodes can move, and is preferably a range around the specimen dropping position. In the present embodiment, the illuminance in the measurement range is used for both the reference amount and the determination amount, but as long as the reference amount and the determination amount are unified, any other index related to light that changes due to the presence of nematodes can be used as the amount related to light.

Next, in steps Sto S, the reference amount and the determination amount are compared to determine whether the determination amount has increased, has not changed, or has decreased. More specifically, first, in step S, a value used for comparison between the reference amount and the determination amount is calculated. In the present embodiment, a difference obtained by subtracting the reference amount from the determination amount is calculated. Alternatively, for example, a ratio obtained by dividing the determination amount by the reference amount may be calculated and used for comparison between the reference amount and the determination amount.

Next, in step S, the value calculated in step Sis compared with an upper limit value. When the value calculated in step Sexceeds the upper limit value, it is considered that the determination amount has increased (the illuminance in the measurement range has increased) after the dropping of the specimen, and a red rank is determined in step S. In this case, it is considered that the nematodes in the container have exhibited the attracting behavior, and it can be estimated that the subject may have cancer.

When the value does not exceed the upper limit value in step S, the process proceeds to step S, and the value calculated in step Sis compared with a lower limit value. When the value is less than the lower limit value, it is considered that the determination amount has decreased (the illuminance in the measurement range has decreased) after the dropping of the specimen, the process proceeds to step S, and a blue rank is determined. In this case, it is considered that the nematodes in the container have exhibited the repelling behavior, and it can be estimated that a possibility that the subject has cancer is low.

When the value is not less than the lower limit value in step S, it is considered that there is no change in the determination amount (there is no change in illuminance in the measurement range) before and after the dropping of the specimen, the process proceeds to step S, and a yellow rank is determined. In this case, there is little change in identifying whether the behavior of the nematodes in the container is the attracting behavior or the repelling behavior, and it can be considered as the noise behavior.

Here, there is data that the accuracy of a cancer inspection using the reaction of the nematodes to the urine is about 85%, and there is still a problem such as difficulty in identifying the site of cancer at the present time, while the accuracy is higher than that in other methods. Therefore, it is assumed that the method according to the present invention is used not for diagnosis of cancer but for simple determination.

For example, in the case of the blue rank, since the possibility that the subject has cancer is low, eligibility for insurance as a healthy person may be given. As described above, the present invention can be used for simple examination of eligibility for insurance. On the other hand, in the case of the red rank or the yellow rank, since there is a possibility that the subject has cancer, it is recommended to perform determination again by the determination method of the present invention or to perform a careful inspection by another method.

Note that the above procedure is an example, and can be arbitrarily changed. For example, in the present embodiment, the reference amount is measured before the dropping of the specimen, but the reference amount may be measured immediately after the dropping of the specimen. Here, “immediately after the dropping of the specimen” indicates after the lapse of such a short time that the attracting behavior or the repelling behavior of the nematodes does not occur after the dropping of the specimen. As described above, if the measured value is a measured value before the attracting behavior or the repelling behavior of the nematodes occurs, there is no problem even when the measured value is used as a comparison target with respect to the determination amount after the movement, so that the measured value can be similarly used as the reference amount.

In addition, for example, in steps $6 to S, it is sufficient that stages can be divided into three stages of red, blue, and yellow on the basis of the value calculated in step S, and the upper limit value and the lower limit value, and the order of comparison may be changed. That is, for example, the order of step Sand step Smay be changed.

In addition, each process excluding step Smay be executed by a computer. Specifically, for example, it is assumed that a microcomputer, a storage device, and the like are provided in a measurement unit of a measurement device to be described later, step Sis executed after a predetermined time from step S, and the computer executes the calculations of steps Sto S.

Next, a container, a measurement device, and a floor plate used in the present embodiment will be described with reference to.

are views illustrating a structure of a petri dish used as the container in the present embodiment. As illustrated in, a petri dishincludes a container main body C and a lid body L that covers the container main body C.

As illustrated in, the lid body L has a substantially triangular shape in plan view, and has one through hole Lcommunicating the container main body C with an external space and three inclined surfaces Lon a top surface thereof. In addition, in order to be able to measure the illuminance (amount related to light) in a state where the lid body L is mounted, it is preferable that at least a portion of the lid body L that is in contact with immediately above the measurement range is made of a material that transmits light. In the present embodiment, the lid body L includes a transmissive portion formed in a shape substantially equidistant from the through hole L.

More specifically, the through hole Lis formed substantially at the center of the top surface. Each of the inclined surfaces Lis defined by a ridge E extending from each corner portion of the top surface toward the through hole Lso as to have a substantially uniform area, and is formed so as to be gradually inclined downward toward the through hole L. In the present embodiment, a diameter Φof the through hole Lis configured to be about 9 mm. Here, if a transmissive portion made of a material that transmits light is provided only around the through hole L, and the other portions are shielded from light, it is possible to reliably set the periphery of the through hole L, which is the dropping position of the specimen, as a measurement range.

As illustrated in, the lid body L has a side wall portion Lextending downward from a peripheral edge of the top surface.

Although an inclination angle θof each inclined surface Lis about 10 degrees, the inclined surface may be inclined at an inclination angle larger than the inclination angle θin order to increase the arrival speed of the dropped liquid to the through hole L.